From jop at astro.columbia.edu  Fri Mar  1 12:46:18 2019
From: jop at astro.columbia.edu (Joe Patterson)
Date: Fri, 1 Mar 2019 12:46:18 -0500
Subject: (cba:news) AM CVn and T Pyx
Message-ID: <2d67b9f8-a87c-ee08-eb64-0d8b542b3ae4@astro.columbia.edu>


Hi CBAers,

It's not exactly "news", but I just wanted to cheer-lead for two of our 
absolute favorite stars: AM CVn and T Pyx.  Both are in fine position 
for observing - T Pyx somewhat (but not much) toward the end of its 
prime season, and AM CVn somewhat (but not much)before the middle of its 
prime season.  Where "prime" means transiting at local midnight.

These two stars probably represent the end-states of most CVs: one 
spiralling out rapidly, the other spiralling in.  We're the only ones 
who really know this (sssshhhh...), so it's up to us to get these rates 
of in/out-spiral as accurately as we can.  Although we observe them a 
lot, it's always the latest data which has the highest weight in 
measuring these rates.  So I hope you'll give these stars a high 
priority in your March observing... and reward them with *long* nightly 
runs.

Just for your computing pleasure, I'm attaching a recent time series for 
these stars: a 5-day time series on AM CVn, and  9-day sequence on T 
Pyx.  Both a "zeroed" (mean subtracted), which aids in period-finding.
The Tpyx series is courtesy of Josch, Gordon, and Peter Nelson.  The AM 
CVn series is courtesy of David Cejudo, Tonny, Shawn Dvorak, Geoff 
Stone, ken menzies, and stephen brincat.  Try your period-finding 
routines on them.

joe
____________________________________________________________
Center for Backyard Astrophysics (CBA) mailing lists
https://cbastro.org/communications/mailing-lists/ 

From jp42 at columbia.edu  Fri Mar  1 14:06:33 2019
From: jp42 at columbia.edu (Joe Patterson)
Date: Fri, 1 Mar 2019 14:06:33 -0500
Subject: (cba:news) Fwd:  AM CVn and T Pyx
In-Reply-To: <2d67b9f8-a87c-ee08-eb64-0d8b542b3ae4@astro.columbia.edu>
References: <2d67b9f8-a87c-ee08-eb64-0d8b542b3ae4@astro.columbia.edu>
Message-ID: <cde272db-2242-0dfc-8cc3-33000b3e09ab@columbia.edu>

Sorry folks, I forgot the attachment.



-------- Forwarded Message --------
Subject: 	(cba:news) AM CVn and T Pyx
Date: 	Fri, 1 Mar 2019 12:46:18 -0500
From: 	Joe Patterson <jop at astro.columbia.edu>
Reply-To: 	cba-chat at cbastro.org
To: 	cba-news at cbastro.org




Hi CBAers,

It's not exactly "news", but I just wanted to cheer-lead for two of our 
absolute favorite stars: AM CVn and T Pyx. Both are in fine position for 
observing - T Pyx somewhat (but not much) toward the end of its prime 
season, and AM CVn somewhat (but not much)before the middle of its prime 
season. Where "prime" means transiting at local midnight.

These two stars probably represent the end-states of most CVs: one 
spiralling out rapidly, the other spiralling in. We're the only ones who 
really know this (sssshhhh...), so it's up to us to get these rates of 
in/out-spiral as accurately as we can. Although we observe them a lot, 
it's always the latest data which has the highest weight in measuring 
these rates. So I hope you'll give these stars a high priority in your 
March observing... and reward them with *long* nightly runs.

Just for your computing pleasure, I'm attaching a recent time series for 
these stars: a 5-day time series on AM CVn, and 9-day sequence on T Pyx. 
Both a "zeroed" (mean subtracted), which aids in period-finding.
The Tpyx series is courtesy of Josch, Gordon, and Peter Nelson. The AM 
CVn series is courtesy of David Cejudo, Tonny, Shawn Dvorak, Geoff 
Stone, ken menzies, and stephen brincat. Try your period-finding 
routines on them.

joe
____________________________________________________________
Center for Backyard Astrophysics (CBA) mailing lists
https://cbastro.org/communications/mailing-lists/
____________________________________________________________
Center for Backyard Astrophysics (CBA) mailing lists
https://cbastro.org/communications/mailing-lists/ 

From jop at astro.columbia.edu  Fri Mar  1 14:12:09 2019
From: jop at astro.columbia.edu (Joe Patterson)
Date: Fri, 1 Mar 2019 14:12:09 -0500
Subject: (cba:news) Fwd: test
In-Reply-To: <efb325ba-6cc7-870d-0271-27c105066799@astro.columbia.edu>
References: <efb325ba-6cc7-870d-0271-27c105066799@astro.columbia.edu>
Message-ID: <bb79f2ec-f12e-f706-d705-7e0202b957cd@astro.columbia.edu>

One more try.  This getting mysterious.


-------- Forwarded Message --------
Subject: test
Date: Fri, 1 Mar 2019 14:10:54 -0500
From: Joe Patterson <jop at astro.columbia.edu>
To: jop at astro.columbia.edu


____________________________________________________________
Center for Backyard Astrophysics (CBA) mailing lists
https://cbastro.org/communications/mailing-lists/ 

From jp42 at columbia.edu  Mon Mar 11 10:09:41 2019
From: jp42 at columbia.edu (Joe Patterson)
Date: Mon, 11 Mar 2019 10:09:41 -0400
Subject: (cba:news) Fwd: (cba:chat) ASASSN-18ey brightening
In-Reply-To: <CANSMr_+s1iA2+sUREh2ERQdHUsjGRYK_bKUYxbgR1FCcCzwFTA@mail.gmail.com>
References: <CANSMr_+s1iA2+sUREh2ERQdHUsjGRYK_bKUYxbgR1FCcCzwFTA@mail.gmail.com>
Message-ID: <c294a2dd-dfe7-7d18-1388-ad5f686c7723@columbia.edu>

Whoa!? Hard as it is (because of the airmass in March), see what you get 
on this apparent "rebrightening"!


joe p



-------- Forwarded Message --------
Subject: 	(cba:chat) ASASSN-18ey brightening
Date: 	Mon, 11 Mar 2019 09:00:04 -0500
From: 	Joe Ulowetz <joe700a at gmail.com>
Reply-To: 	cba-chat at cbastro.org
To: 	cba-chat at cbastro.org



I measured ASASSN-18ey at mag?15.474 this morning, about 2 magnitudes 
brighter then I've seen it the past 2 months. It was?17.177 just 4 days ago.

Thanks,
-Joe U.


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From jop at astro.columbia.edu  Tue Mar 12 09:02:32 2019
From: jop at astro.columbia.edu (Joe Patterson)
Date: Tue, 12 Mar 2019 09:02:32 -0400
Subject: (cba:news) ASASSN-18ey... and AM CVn
Message-ID: <97f63498-f415-2ad8-fd25-43c1b406cd6b@astro.columbia.edu>

Hi CBAers,

Joe U's discovery of the rebrightening of our old friend from last year 
is posted on ATel 12567 (they post these things in <15 minutes, so be 
careful when you send!).  Let's brave those cold March mornings to find 
what's going on with Maxi.  With that long period of 17 hours. we can't 
cover an orbit (except by splicing data from several longitudes).  But 
with a V filter, you can start well above our usual limit of 2.0 
airmasses (even to 3.0), because the extinction is fairly low and 
well-defined.

And let's go after AM CVn with similar intensity.  March is a great 
season for this star, and although the raw light curve doesn't look like 
much, it is flashing at least two superhumps (positive at 525.6 s - the 
first overtone - plus the 1028 s orbital signal.  With enough time 
baseline, we get to see those periods *change* - minutely but with great 
consequences for the star's structure and evolution.  LONG time series 
are needed, but stick with a clear or minus-blue filter (so adhere to 
the <2.0 airmass convention).

joe p

____________________________________________________________
Center for Backyard Astrophysics (CBA) mailing lists
https://cbastro.org/communications/mailing-lists/ 

From jop at astro.columbia.edu  Sun Mar 24 11:04:31 2019
From: jop at astro.columbia.edu (Joe Patterson)
Date: Sun, 24 Mar 2019 11:04:31 -0400
Subject: (cba:news) the "ultracompact" project: AM CVn, HP Lib, CR Boo
Message-ID: <0bb2153c-bd2c-0631-0112-9172327c6e89@astro.columbia.edu>

Hi CBAers,

I wanted to write in some detail about the AM CVn project underway.  In 
our Skillman et al. 1999, we spelled out the star's basic period 
structure in full detail: an orbital period of 1028.7322 s, a positive 
superhump at 525.6 s (actually its "subharmonic" at 1051.2), and a 
negative superhump at 1011.4 s.  That paper also listed many other sum 
and difference frequencies present at lower amplitude; but these are the 
basics.

Many theoretical and observational papers on superhumping CVs have 
ascertained the origin of positive superhumps: an eccentric instability 
at the 3:1 orbital resonance in the disk.  Because it's seated in the 
disk, it doesn't have high stability, but wanders in phase on a 
timescale of days to weeks.  The orbital signal is weaker (just 0.008 
mag full amplitude), which is why we're the only people (so far; TESS 
will see it easily) who have ever detected it.  Nevertheless, we've 
obtained timings over 27 years (at least) and found the orbital period 
slowly decreasing, on a timescale of 60 million years.  This arises from 
a combination of mass transfer (which increases the period) and 
gravitational radiation (which decreases the period).  AM CVn is 
expected to be one of the brightest steady Galactic sources in the next 
generation of space-based gravitational-wave detectors.

Thanks in no small measure to David Cejudo's relentless coverage from 
Madrid, the 2019 coverage has confirmed the Porb change - our main goal. 
  Great!  But now we're within reach of another goal, not yet achieved 
for any star.  Do the positive and negative superhumps change their 
periods in phase, in anti-phase, or uncorrelated?   If the *negative* 
superhump arises also at the 3:1 resonance (not known!), then it's 
reasonable to expect that the signals will be in anti-phase.  Any other 
result... well, we'll have to think that one through!

I doubt that any other star will enable such a test, because AM CVn's 
constancy in brightness is unparalleled (basically within 0.02-0.03 
mag).  So let's KEEP IT GOING - at least another month.

BTW the preferred term nowadays is "ultracompacts", rather than AM CVns, 
because there is also a collection of similar binaries (Porb<50 min) 
which have neutron-star or black-hole accretors.  Much less is known 
about them, but the physics is likely identical (except very, very close 
to the accretor).

Two other AM CVns (oops, ultracompacts) are candidates, and bright 
enough for a similar, but less detailed, test.  These are HP Lib and CR 
Boo.  Negative superhumps haven't even been *discovered* in these stars 
(yet), so we have a way to go.  Nor is the orbital period known for 
sure.  But we can find these things, if they're present at anything 
exceeding ~0.003 mag.  Behold the power of time series!  They're also 
seasonally appropriate, and with friendly coordinates - accessible to 
everyone.  Let's get going on these stars!

joe p

____________________________________________________________
Center for Backyard Astrophysics (CBA) mailing lists
https://cbastro.org/communications/mailing-lists/ 

From jp42 at columbia.edu  Mon Mar 25 08:20:49 2019
From: jp42 at columbia.edu (Joe Patterson)
Date: Mon, 25 Mar 2019 08:20:49 -0400
Subject: (cba:news) CR Boo, HP Lib, IM Nor, WX Cen, NR TrA, V407 Lup
In-Reply-To: <BYAPR19MB2581C25B31B8C3C36FD7EFE3A05E0@BYAPR19MB2581.namprd19.prod.outlook.com>
References: <0bb2153c-bd2c-0631-0112-9172327c6e89@astro.columbia.edu>
 <BYAPR19MB2581C25B31B8C3C36FD7EFE3A05E0@BYAPR19MB2581.namprd19.prod.outlook.com>
Message-ID: <98c00645-444e-2988-0b3e-cc7924c6de8f@columbia.edu>

Among those stars:

T Pyx done for the season.? We have enough to nail down the ephemeris - 
and hopefully the physics!

HP Lib and CR Boo: It's important to start the HP Lib season, which 
would be about now (late March).? But about a week of coverage would 
nail down the early-season phase of the periodic signal(s??). After 
that, CR Boo wins.? Because it has outbursts, unlike AM CVn and HP Lib, 
it's hard to say in advance what the priority-setting standard is (are 
outbursts more or less informative than quiescence?)? Except for one 
thing: its transitions to? 17th magnitude, which used to be rare and 
probably still are, are of VERY high interest,? A few weeks of coverage 
will make these priority decisions easier.

There are some other southern stars asking for coverage.

1. IM Nor.? Got a paper almost ready to roll.? A few 2019 eclipse 
timings will fortify the long-term ephemeris.? It's far-southern and 
normally mag 18 out of eclipse, so likely only in Gordon's territory.

2. WX Cen. Another "V Sge" star, like IM Nor and T Pyx, with very rapid 
change in Porb. A bright star, friendly for all scopes... but very 
desirous of long runs, since Porb is long and the eclipses somewhat 
shallow (~0.5 mag).

3. NR TrA.? We've been tracing out the orbital light curve since its 
2008 outburst.? Let's get a high-quality result for 2019!

4. V407 Lup.? Time to start the season on this fascinating and possibly 
unique star, a 2016 nova. Paper in an advanced state on this guy, but 
needing another season.

We've gotten great results from our surveys of the post-eruption orbital 
light curves, in general.? Koji Mukai's list of recent novae is an 
excellent source of material to study:

https://asd.gsfc.nasa.gov/Koji.Mukai/novae/novae.html

The great majority of these targets are desirous of LONG observations... 
but the AM CVn stars are less finicky than the others.


joe p


On 3/24/2019 11:54 PM, Gordon Myers wrote:
> Joe, what's priority among CR Boo, HP Lib and T Pyx?
>
> Gordon
>
> -----Original Message-----
> From: cba-chat <cba-chat-bounces at cbastro.org> On Behalf Of Joe Patterson
> Sent: Sunday, March 24, 2019 8:05 AM
> To: cba-news at cbastro.org; cba-chat at cbastro.org
> Subject: (cba:chat) the "ultracompact" project: AM CVn, HP Lib, CR Boo
>
> Hi CBAers,
>
> I wanted to write in some detail about the AM CVn project underway.  In our Skillman et al. 1999, we spelled out the star's basic period structure in full detail: an orbital period of 1028.7322 s, a positive superhump at 525.6 s (actually its "subharmonic" at 1051.2), and a negative superhump at 1011.4 s.  That paper also listed many other sum and difference frequencies present at lower amplitude; but these are the basics.
>
> Many theoretical and observational papers on superhumping CVs have ascertained the origin of positive superhumps: an eccentric instability at the 3:1 orbital resonance in the disk.  Because it's seated in the disk, it doesn't have high stability, but wanders in phase on a timescale of days to weeks.  The orbital signal is weaker (just 0.008 mag full amplitude), which is why we're the only people (so far; TESS will see it easily) who have ever detected it.  Nevertheless, we've obtained timings over 27 years (at least) and found the orbital period slowly decreasing, on a timescale of 60 million years.  This arises from a combination of mass transfer (which increases the period) and gravitational radiation (which decreases the period).  AM CVn is expected to be one of the brightest steady Galactic sources in the next generation of space-based gravitational-wave detectors.
>
> Thanks in no small measure to David Cejudo's relentless coverage from Madrid, the 2019 coverage has confirmed the Porb change - our main goal.
>    Great!  But now we're within reach of another goal, not yet achieved for any star.  Do the positive and negative superhumps change their
> periods in phase, in anti-phase, or uncorrelated?   If the *negative*
> superhump arises also at the 3:1 resonance (not known!), then it's reasonable to expect that the signals will be in anti-phase.  Any other result... well, we'll have to think that one through!
>
> I doubt that any other star will enable such a test, because AM CVn's constancy in brightness is unparalleled (basically within 0.02-0.03 mag).  So let's KEEP IT GOING - at least another month.
>
> BTW the preferred term nowadays is "ultracompacts", rather than AM CVns, because there is also a collection of similar binaries (Porb<50 min) which have neutron-star or black-hole accretors.  Much less is known about them, but the physics is likely identical (except very, very close to the accretor).
>
> Two other AM CVns (oops, ultracompacts) are candidates, and bright enough for a similar, but less detailed, test.  These are HP Lib and CR Boo.  Negative superhumps haven't even been *discovered* in these stars (yet), so we have a way to go.  Nor is the orbital period known for sure.  But we can find these things, if they're present at anything exceeding ~0.003 mag.  Behold the power of time series!  They're also seasonally appropriate, and with friendly coordinates - accessible to everyone.  Let's get going on these stars!
>
> joe p
>
> ____________________________________________________________
> Center for Backyard Astrophysics (CBA) mailing lists
> https://eur04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fcbastro.org%2Fcommunications%2Fmailing-lists%2F&amp;data=02%7C01%7C%7Cf134eddcea924bf8dd3408d6b06a08e3%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636890366788319572&amp;sdata=rEOUAlLuX1m0ZKAFMM3BA7rS%2Bd3N9B97018Ebv%2Bzf18%3D&amp;reserved=0
> ____________________________________________________________
> Center for Backyard Astrophysics (CBA) mailing lists
> https://cbastro.org/communications/mailing-lists/

____________________________________________________________
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From jp42 at columbia.edu  Mon Mar 25 10:50:25 2019
From: jp42 at columbia.edu (Joe Patterson)
Date: Mon, 25 Mar 2019 10:50:25 -0400
Subject: (cba:news) Post-outburst orbital light curves of novae
In-Reply-To: <98c00645-444e-2988-0b3e-cc7924c6de8f@columbia.edu>
References: <0bb2153c-bd2c-0631-0112-9172327c6e89@astro.columbia.edu>
 <BYAPR19MB2581C25B31B8C3C36FD7EFE3A05E0@BYAPR19MB2581.namprd19.prod.outlook.com>
 <98c00645-444e-2988-0b3e-cc7924c6de8f@columbia.edu>
Message-ID: <eb4fa890-e437-8712-147b-f41b9624ce23@columbia.edu>

More on this short- and long-term project of studying the orbital light 
curves of recent novae...

This is truly a project which will have long-term significance.? If we 
only knew the just-after- eruption orbital light curves of the famous 
novae - DQ Her, V603 Aql, GK Per, RR Pic, CP Pup... what a bonanza that 
would be!? The reason is that in early post-eruption, there's a big ol' 
luminous white dwarf, which illuminates the accretion disk.? After the 
WD temperature drops below about 300000 K, it's no longer observable in 
X-ray telescopes.? But "absence of evidence is not evidence of 
absence"... and there's a critical and open question: on what timescale 
does the binary transition from illuminating-WD-dominated to 
accretion-dominated?? The orbital light curve (and eclipse shapes, for 
the binaries of higher inclination) is a good probe of this.? We pretty 
much know the story 50-100 years after outburst, but we'd like to know 3-10!

The novae which reached V>10 in outburst are generally not worth 
pursuing.? Same for the galactic center guys.? It's the bright ones 
which are worth the effort. Koji's links will tell you a lot of info 
about these.? You'd be surprised how little is known about the 
post-novae: a flurry of ATels, maybe 2 published papers... and then: 
hey, it's on to the next nova.? Claus Tappert and Linda Schmidtobreick 
are exceptions; they pay close attention to the old novae on all 
relevant timescales, and have some big glass available (both based in 
Chile). Otherwise, it's somewhat of an orphaned subject.? 
(Spectroscopically, Fred Walter - the source of the "SMARTS" links - is 
the world's authority on the subject.)

That's some background.? Most old novae have *nothing at all* known 
about their behavior 5-20 years after outburst.? Even if you have just 
an upper limit on magnitude - the minimal quantum of information - it 
could be useful.? Collect 'em and send!

joe p


On 3/25/2019 8:20 AM, Joe Patterson wrote:
> Among those stars:
>
> T Pyx done for the season.? We have enough to nail down the ephemeris 
> - and hopefully the physics!
>
> HP Lib and CR Boo: It's important to start the HP Lib season, which 
> would be about now (late March).? But about a week of coverage would 
> nail down the early-season phase of the periodic signal(s??). After 
> that, CR Boo wins.? Because it has outbursts, unlike AM CVn and HP 
> Lib, it's hard to say in advance what the priority-setting standard is 
> (are outbursts more or less informative than quiescence?)? Except for 
> one thing: its transitions to? 17th magnitude, which used to be rare 
> and probably still are, are of VERY high interest,? A few weeks of 
> coverage will make these priority decisions easier.
>
> There are some other southern stars asking for coverage.
>
> 1. IM Nor.? Got a paper almost ready to roll.? A few 2019 eclipse 
> timings will fortify the long-term ephemeris.? It's far-southern and 
> normally mag 18 out of eclipse, so likely only in Gordon's territory.
>
> 2. WX Cen. Another "V Sge" star, like IM Nor and T Pyx, with very 
> rapid change in Porb. A bright star, friendly for all scopes... but 
> very desirous of long runs, since Porb is long and the eclipses 
> somewhat shallow (~0.5 mag).
>
> 3. NR TrA.? We've been tracing out the orbital light curve since its 
> 2008 outburst.? Let's get a high-quality result for 2019!
>
> 4. V407 Lup.? Time to start the season on this fascinating and 
> possibly unique star, a 2016 nova. Paper in an advanced state on this 
> guy, but needing another season.
>
> We've gotten great results from our surveys of the post-eruption 
> orbital light curves, in general.? Koji Mukai's list of recent novae 
> is an excellent source of material to study:
>
> https://asd.gsfc.nasa.gov/Koji.Mukai/novae/novae.html
>
> The great majority of these targets are desirous of LONG 
> observations... but the AM CVn stars are less finicky than the others.
>
>
> joe p
>
>
> On 3/24/2019 11:54 PM, Gordon Myers wrote:
>> Joe, what's priority among CR Boo, HP Lib and T Pyx?
>>
>> Gordon
>>
>> -----Original Message-----
>> From: cba-chat <cba-chat-bounces at cbastro.org> On Behalf Of Joe Patterson
>> Sent: Sunday, March 24, 2019 8:05 AM
>> To: cba-news at cbastro.org; cba-chat at cbastro.org
>> Subject: (cba:chat) the "ultracompact" project: AM CVn, HP Lib, CR Boo
>>
>> Hi CBAers,
>>
>> I wanted to write in some detail about the AM CVn project underway.? 
>> In our Skillman et al. 1999, we spelled out the star's basic period 
>> structure in full detail: an orbital period of 1028.7322 s, a 
>> positive superhump at 525.6 s (actually its "subharmonic" at 1051.2), 
>> and a negative superhump at 1011.4 s. That paper also listed many 
>> other sum and difference frequencies present at lower amplitude; but 
>> these are the basics.
>>
>> Many theoretical and observational papers on superhumping CVs have 
>> ascertained the origin of positive superhumps: an eccentric 
>> instability at the 3:1 orbital resonance in the disk.? Because it's 
>> seated in the disk, it doesn't have high stability, but wanders in 
>> phase on a timescale of days to weeks.? The orbital signal is weaker 
>> (just 0.008 mag full amplitude), which is why we're the only people 
>> (so far; TESS will see it easily) who have ever detected it.? 
>> Nevertheless, we've obtained timings over 27 years (at least) and 
>> found the orbital period slowly decreasing, on a timescale of 60 
>> million years.? This arises from a combination of mass transfer 
>> (which increases the period) and gravitational radiation (which 
>> decreases the period).? AM CVn is expected to be one of the brightest 
>> steady Galactic sources in the next generation of space-based 
>> gravitational-wave detectors.
>>
>> Thanks in no small measure to David Cejudo's relentless coverage from 
>> Madrid, the 2019 coverage has confirmed the Porb change - our main goal.
>> ?? Great!? But now we're within reach of another goal, not yet 
>> achieved for any star.? Do the positive and negative superhumps 
>> change their
>> periods in phase, in anti-phase, or uncorrelated??? If the *negative*
>> superhump arises also at the 3:1 resonance (not known!), then it's 
>> reasonable to expect that the signals will be in anti-phase.? Any 
>> other result... well, we'll have to think that one through!
>>
>> I doubt that any other star will enable such a test, because AM CVn's 
>> constancy in brightness is unparalleled (basically within 0.02-0.03 
>> mag).? So let's KEEP IT GOING - at least another month.
>>
>> BTW the preferred term nowadays is "ultracompacts", rather than AM 
>> CVns, because there is also a collection of similar binaries (Porb<50 
>> min) which have neutron-star or black-hole accretors.? Much less is 
>> known about them, but the physics is likely identical (except very, 
>> very close to the accretor).
>>
>> Two other AM CVns (oops, ultracompacts) are candidates, and bright 
>> enough for a similar, but less detailed, test.? These are HP Lib and 
>> CR Boo.? Negative superhumps haven't even been *discovered* in these 
>> stars (yet), so we have a way to go.? Nor is the orbital period known 
>> for sure.? But we can find these things, if they're present at 
>> anything exceeding ~0.003 mag. Behold the power of time series!? 
>> They're also seasonally appropriate, and with friendly coordinates - 
>> accessible to everyone.? Let's get going on these stars!
>>
>> joe p
>>
>> ____________________________________________________________
>> Center for Backyard Astrophysics (CBA) mailing lists
>> https://eur04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fcbastro.org%2Fcommunications%2Fmailing-lists%2F&amp;data=02%7C01%7C%7Cf134eddcea924bf8dd3408d6b06a08e3%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636890366788319572&amp;sdata=rEOUAlLuX1m0ZKAFMM3BA7rS%2Bd3N9B97018Ebv%2Bzf18%3D&amp;reserved=0 
>>
>> ____________________________________________________________
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From jop at astro.columbia.edu  Wed Mar 27 11:24:09 2019
From: jop at astro.columbia.edu (Joe Patterson)
Date: Wed, 27 Mar 2019 11:24:09 -0400
Subject: (cba:news) AM CVn and Maxie
Message-ID: <8f77eee6-8a08-0c76-1a76-0e0402bd8e27@astro.columbia.edu>

Hi (mostly northern) CBAers,

The AM CVn data rolling in is a thing of beauty.  On most mornings, my 
first move is to check the overnight mail for new data... and then do a 
preliminary analysis before the first sip of coffee.  A nice preview of 
my retired-professor life!  (A few years off.)

I just wanted to check a few things.

1. Except for Jim Seargeant who specifies HJD, I assume that everyone is 
using JD, as the labels say.  Correct me if I'm wrong!  But Jim, you 
don't need to change, at least for me; your data is so good that I 
wouldn't change a thing.  (I'm not sure whether AAVSO cares, as long as 
the label is correct.)

2. Calibration.  Most people are covering AM CVn unfiltered, which is 
fine... and arguably better since the signal is weak (0.01-0.02 mag). 
However, it does mean that the almost-constant reported magnitudes are 
offset from each other by as much as 0.35 mag - reflecting different 
bandpasses of detectors and choices of comparison stars... and possibly, 
at a lower level, sky conditions.  It matters little to me since I 
routinely zero out those offsets - very easy to do when there's a lot of 
data.  But for those of you who take a lot of data, I'm interested in 
your opinion on this: do you see nightly variability exceeding ~0.05 mag 
in your data?   I've never noticed, but am so busy with the zeroing-out 
that I've practically paralyzed  my ability to see such things.  Lemme know!

AM CVn is one of the most famous and archetypal CVs in the sky... yet 
has no C and barely any V, except in its name. What a fascinating star!

Re Maxie = ASASSN-18ey.  Having rebrightened on its one-year 
anniversary, the star is hanging in there at 14.0... with some huge 
(~0.5 mag?) very fast variability.  For this star, generally a V filter 
is best, because the flux will get compared to filtered measurements at 
many other wavelengths.  HOWEVER, you might be interested in studying 
that ultrafast variability.  If you can manage, say, 5-10 s monitoring, 
you could possibly study it.  And for that I'd recommend no filter, 
because you need all the photons.

Finally, I'm inclined to say: time to pull the plug (end coverage) on BH 
Lyn.  Results later...

joe p

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From jp42 at columbia.edu  Wed Mar 27 12:02:50 2019
From: jp42 at columbia.edu (Joe Patterson)
Date: Wed, 27 Mar 2019 12:02:50 -0400
Subject: (cba:news) Fwd: [vsnet-alert 23090] ASASSN-19hl - bright (11m)
 large-amplitude object in Puppis
In-Reply-To: <CA+ANhyd_Ondw5RH59CfuEZ1UpaM7rSNUmZr8fqALwEEvK+ideA@mail.gmail.com>
References: <CA+ANhyd_Ondw5RH59CfuEZ1UpaM7rSNUmZr8fqALwEEvK+ideA@mail.gmail.com>
Message-ID: <a3f7c7d7-f8ce-694b-5e7a-ccae28a80307@columbia.edu>

Hmmm, this looks too good to pass up.? WZ Sge-type dwarf novae are not 
particularly rare, but we don't get much crack at ones this close and 
bright.? Let's jump on this guy!? As long as it's this bright, a V 
filter is better since it will allow you to stretch the observations out 
to slightly higher airmass, maybe as much as 2.7-3.0 airmasses.? (Puppis 
is getting to be a challenge in late March and April.)

joe p



-------- Forwarded Message --------
Subject: 	[vsnet-alert 23090] ASASSN-19hl - bright (11m) large-amplitude 
object in Puppis
Date: 	Wed, 27 Mar 2019 18:25:00 +0300
From: 	Denis Denisenko d.v.denisenko at gmail.com via vsnet-alert 
<vsnet-alert at ooruri.kusastro.kyoto-u.ac.jp>
Reply-To: 	Denis Denisenko <d.v.denisenko at gmail.com>
To: 	vsnet-alert at ooruri.kusastro.kyoto-u.ac.jp



ASAS-SN has reported a new bright object to Transient Name Server, see
https://wis-tns.weizmann.ac.il/object/2019ckc

AT 2019ckc = ASASSN-19hl
20190327.03 10.9g ASAS-SN (K. Z. Stanek, C. S. Kochanek, ASAS-SN team)

I have obtained BVR images of this object with iTelescope.Net T09
instrument (0.127-m f/5.6 refractor + CCD, image scale 2.75"/pixel) in
Siding Spring, Australia. Three 60-second exposures were obtained in
each filter from 13:28 to 13:46 UT on 2019 Mar. 27th.

Using the nearby TYC 7125-2955-1 as a reference star, the following
magnitudes were measured for ASASSN-19hl:

ASASSN-19hl
20190327.563 11.34R T09
20190327.568 11.06V T09
20190327.573 11.08B T09

Color-combined iTelescope.Net T09 image (10'x10' FOV):
http://scan.sai.msu.ru/~denis/ASASSN-19hl-T09-20190327-RGB.jpg

The position of the OT is 08 11 33.50 -32 44 35.1 (+/-0.3 arcsec).
There is a blue 19th mag star near this position in USNO-B1.0, PPMXL
catalogs and Gaia DR2.

Color-combined (JRIR) DSS image (10'x10' FOV):
http://scan.sai.msu.ru/~denis/ASASSN-19hl-JRIR.jpg

Gaia DR2 position is 08 11 33.50 -32 44 35.47 (within 0.4" of the
iTelescope.Net measurement) and Gmag=19.56. According to Gaia DR2,
parallax is 3.12+/-0.42 mas which corresponds to the distance 320+/-42
pc. Based on the absolute magnitude at quiescence (M~12) and in
outburst (M~4), this object is likely a dwarf nova of WZ Sge type.

Denis Denisenko


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From jp42 at columbia.edu  Thu Mar 28 08:55:32 2019
From: jp42 at columbia.edu (Joe Patterson)
Date: Thu, 28 Mar 2019 08:55:32 -0400
Subject: (cba:news) Fwd: (cba:chat) Berto's inspired update of "Lew's
 Version of Koji Mukai's List"
In-Reply-To: <CAPvxGuXQwGZkeUNm8ZZBLNbJuiKW0-AnoiE96NWyFkhT3dd7Rg@mail.gmail.com>
References: <CAPvxGuXQwGZkeUNm8ZZBLNbJuiKW0-AnoiE96NWyFkhT3dd7Rg@mail.gmail.com>
Message-ID: <7cd05222-06a0-2b3f-58d0-b6de591a4400@columbia.edu>

I just wanted to get this great research tool - of Koji, Lew, and Berto 
- out there to a slightly wider audience!? It's perfect for those 
wishing to contribute to the long-term ephemeris for these stars 
(basically needing a few good time-series photometry runs per observing 
season)... and plenty useful for any IP-related program.


joe p



-------- Forwarded Message --------
Subject: 	(cba:chat) Berto's inspired update of "Lew's Version of Koji 
Mukai's List"
Date: 	Wed, 27 Mar 2019 21:34:50 +0000
From: 	Lew Cook <lew.cook at gmail.com>
Reply-To: 	cba-chat at cbastro.org
To: 	cba-chat <cba-chat at cbastro.org>



I sent out a shortened "quick look" at the list that Koji Mukai 
published at:
https://asd.gsfc.nasa.gov/Koji.Mukai/iphome/catalog/alpha.html
Sincethen, Berto Monard updated his observationswhich prompted me to 
refresh my list. Slowly*, I did so. Here it is as an image and as an 
Excel spreadsheet.

Lewis M. Cook (Lew)
*While recovering from a badly sprained ankle
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